Buying local has become a bit of a mantra. We understand that it takes a heck of a lot of climate-killing carbon to get that hula hoop from China to Chicago, but it’s easy to let the details slip. Here’s some perspective: Maersk Triple E’s, the world’s largest container ships, measure 1,312 feet from stem to stern and contain 55,000 tons of steel alone. To put that into more relatable terms, that’s 196 LeBron James long and more than a million Rottweilers in weight.

These giant vessels are giant polluters. The largest vessels burn around 16 tons of low-grade, high-sulphur diesel fuel per hour as they ceaselessly plow the world’s oceans at over 25 knots. One studyestimates just one of these gigantic ships spews out as much cancer-causing pollutants as 50 million cars every year, and there are an estimated 90,000 cargo ships around the world. Unfortunately, pending legislation aimed at cleaning up these ships focuses exclusively on sulfur emissions and misses the boat on CO2, one of the driving causes of climate change.